diff --git a/common/ast_rewrite_test.cc b/common/ast_rewrite_test.cc
index 5417b23ac..8a5debbba 100644
--- a/common/ast_rewrite_test.cc
+++ b/common/ast_rewrite_test.cc
@@ -525,7 +525,7 @@ class RewriterExample : public AstRewriterBase {
 
  private:
   absl::Span<const Expr*> path_;
-  absl::optional<int64_t> target_;
+  std::optional<int64_t> target_;
 };
 
 TEST(AstRewrite, SelectRewriteExample) {